Project

# Title Team Members TA Documents Sponsor
91 Automatic Bike Collision Prevention System
 Charlie Wang
Nathan Zhu
Rahul Nayak
 Frey Zhao design_document1.pdf
proposal1.pdf
# Automatic Bike Collision Prevention System

Team Members:
- Rahul Nayak (rn8)
- Charlie Wang (cgwang3)
- Nathan Zhu (nyzhu2)

# Problem

Active pathways like campus sidewalks create high risk scenarios for cyclists and passerby due to oblivious pedestrians and distracted riding. Traditional bicycle bells are reactive rather than proactive, requiring both the cyclist to recognize a potential collision and react by ringing the bell, and pedestrians to acknowledge the bell and move out of the way. The total time to prevent collision can be lengthened if the cyclist’s reaction time was not a consideration. As such, there is a need for an automated alert system that is able to identify and distinguish potential collision hazards before they occur.

# Solution

We will create a handlebar-mounted safety system using three mmWave radar sensors to act as a peripheral vision of sorts. The sensors will be set up such that we have a center sensor, and left and right sensors. The system performs spatial gating, where detections transitioning from peripheral radar sectors into the forward sector are classified as hazards, while detections only in the peripheral radar sectors are ignored. We estimate a time to collision depending on the current distance detected and the distance from past readings, and ring the bell at different volumes accordingly.

# Solution Components

## Subsystem 1: Power

Provide regulated power and system status feedback.

Components:

- Li-ion 18650 Battery: High capacity power source.
- Buck-Boost Converter: Stable 5V/3.3V regulation.
- Status LEDs: Indicators to indicate if the system is on, sensitivity level, and if an object is detected.
- Sensitivity Potentiometer: Allows the rider to adjust the magnitude threshold for different environments.

## Subsystem 2: Radar Sensor Array

Function: Detect object distance.

Components:

- Three HLK-LD2410 24GHz mmWave Radar Modules
- Configuration: 1 center (0°), 2 side angled (30°)
- To create distinct sensors, small 3D printed shields will be set to limit field of view and prevent cross-talking.
- This triangular configuration allows for section-based filtering.
- Due to limited UARTs on the ESP32, the radars should be checked one at a time in a very fast, cyclical manner, which would also help prevent crosstalking.

## Subsystem 3: Processing

Function: Filter noise and determine collision likeliness.

Components:
- ESP32 Microcontroller: UART connection with Radar sensors
- Magnitude thresholding: Ignore low energy reflections such as from pavement or small non-collision objects.
- Time-To-Collision algorithm: Estimate how long it will take until a collision occurs.

## Subsystem 4: Alert System

Function: Create a gradually audible ringing sound depending on the expected collision time.

Components:
- Piezo Buzzer (PS1240): Use Pulse Width Modulation to increase beep frequency
- Three alert stages

# Criterion For Success

The project will be considered successful if all criteria below are met:
- Range performance: Reliably detect objects from 5 meters away.
- Low latency: Detection to audio output is less than 150ms.
- Form factor: Device is compact enough to mount on handlebars.
- False-positive mitigation: Thresholding prevents alarm from triggering for ground objects and other non hazards.
- Peripheral vision: Device is able to detect objects in peripheral vision and keep track of these objects moving into the sight of the center sensor.
- Battery life: Battery should last at least 8 hours on a single charge.

Covert Communication Device

Ahmad Abuisneineh, Srivardhan Sajja, Braeden Smith

Covert Communication Device

Featured Project

**Partners (seeking one additional partner)**: Braeden Smith (braeden2), Srivardhan Sajja (sajja3)

**Problem**: We imagine this product would have a primary use in military/law enforcement application -- especially in dangerous, high risk missions. During a house raid or other sensitive mission, maintaining a quiet profile and also having good situational awareness is essential. That mean's that normal two way radios can't work. And alternatives, like in-ear radios act as outside->in communication only and also reduce the ability to hear your surroundings.

**Solution**: We would provide a series of small pocketable devices with long battery that would use LoRa radios to provide a range of 1-5 miles. They would be rechargeable and have a single recessed soft-touch button that would allow someone to find it inside of pockets and tap it easily. The taps would be sent in real-time to all other devices, where they would be translated into silent but noticeable vibrations. (Every device can obviously TX/RX).

Essentially a team could use a set of predetermined signals or even morse code, to quickly and without loss of situational awareness communicate movements/instructions to others who are not within line-of-sight.

The following we would not consider part of the basic requirements for success, but additional goals if we are ahead of schedule:

We could also imagine a base-station which would allow someone using a computer to type simple text that would be sent out as morse code or other predetermined patterns. Additionally this base station would be able to record and monitor the traffic over the LoRa channels (including sender).

**Solutions Components**:

- **Charging and power systems**: the device would have a single USB-C/Microusb port that would connect to charging circuitry for the small Lithium-ion battery (150-500mAh). This USB port would also connect to the MCU. The subsystem would also be responsible to dropping the lion (3.7-4.2V to a stable 3.3V logic level). and providing power to the vibration motor.

- **RF Communications**: we would rely on externally produced RF transceivers that we would integrate into our PCB -- DLP-RFS1280, https://www.sparkfun.com/products/16871, https://www.adafruit.com/product/3073, .

-**Vibration**: We would have to research and source durable quiet, vibration motors that might even be adjustable in intensity

- **MCU**: We are likely to use the STM32 series of MCU's. We need it to communicate with the transceiver (probably SPI) and also control the vibration motor (by driving some transistor). The packets that we send would need to be encrypted (probably with AES). We would also need it to communicate to a host computer for programming via the same port.

- **Structural**: For this prototype, we'd imagine that a simple 3d printed case would be appropriate. We'd have to design something small and relatively ergonomic. We would have a single recessed location for the soft-touch button, that'd be easy to find by feel.

**Basic criterion for success:** We have at least two wireless devices that can reliably and quickly transfer button-presses to vibrations on the other device. It should operate at at *least* 1km LOS. It should be programmable + chargeable via USB. It should also be relatively compact in size and quiet to use.

**Additional Success Criterion:** we would have a separate, 3rd device that can stay permanently connected to a computer. It would provide some software that would be able to send and receive from the LoRa radio, especially ASCII -> morse code.